JP2010-230117A discloses a technology of permitting a downshift of a sub-transmission mechanism only in a situation where a large drive force is required (an accelerator pedal opening is larger than a predetermined opening and a changing speed of the accelerator pedal opening is higher than a predetermined speed) in a continuously variable transmission with the sub-transmission mechanism.
Since a shift frequency of the sub-transmission mechanism decreases according to this technology, a reduction in drivability due to the repeated occurrence of a shift shock and a reduction in the durability of frictional engagement elements of the sub-transmission mechanism can be suppressed.